RESUMEN
BACKGROUND: The soil-transmitted helminth (STH), Trichuris trichiura colonises the human large intestine where it may modify inflammatory responses, an effect possibly mediated through alterations in the intestinal microbiota. We hypothesised that patent T. trichiura infections would be associated with altered faecal microbiota and that anthelmintic treatment would induce a microbiota resembling more closely that observed in uninfected individuals. MATERIALS AND METHODS: School children in Ecuador were screened for STH infections and allocated to 3 groups: uninfected, T. trichiura only, and mixed infections with T. trichiura and Ascaris lumbricoides. A sample of uninfected children and those with T. trichiura infections only were given anthelmintic treatment. Bacterial community profiles in faecal samples were studied by 454 pyrosequencing of 16 S rRNA genes. RESULTS: Microbiota analyses of faeces were done for 97 children: 30 were uninfected, 17 were infected with T. trichiura, and 50 with T. trichiura and A. lumbricoides. Post-treatment samples were analyzed for 14 children initially infected with T. trichiura alone and for 21 uninfected children. Treatment resulted in 100% cure of STH infections. Comparisons of the microbiota at different taxonomic levels showed no statistically significant differences in composition between uninfected children and those with T. trichiura infections. We observed a decreased proportional abundance of a few bacterial genera from the Clostridia class of Firmicutes and a reduced bacterial diversity among children with mixed infections compared to the other two groups, indicating a possible specific effect of A. lumbricoides infection. Anthelmintic treatment of children with T. trichiura did not alter faecal microbiota composition. DISCUSSION: Our data indicate that patent human infections with T. trichiura may have no effect on faecal microbiota but that A. lumbricoides colonisation might be associated with a disturbed microbiota. Our results also catalogue the microbiota of rural Ecuadorians and indicate differences with individuals from more urban industrialised societies.
Asunto(s)
Heces/microbiología , Microbiota , Tricuriasis/microbiología , Trichuris , Adolescente , Animales , Antihelmínticos/farmacología , Antihelmínticos/uso terapéutico , Bacterias/clasificación , Bacterias/efectos de los fármacos , Bacterias/genética , Niño , Análisis por Conglomerados , Ecuador/epidemiología , Femenino , Humanos , Intestinos/efectos de los fármacos , Intestinos/microbiología , Intestinos/parasitología , Masculino , Microbiota/efectos de los fármacos , ARN de Helminto , ARN Ribosómico 16S , Tricuriasis/tratamiento farmacológico , Tricuriasis/epidemiología , Tricuriasis/parasitología , Trichuris/genéticaRESUMEN
Evidence on the comorbidity between soil-transmitted helminth infections and malaria is scarce and divergent. This study explored the interactions between soil-transmitted helminth infections and uncomplicated falciparum malaria in an endemic area of Colombia. A paired case-control study matched by sex, age and location in Tierralta, Cordoba, was done between January and September 2010. The incident cases were 68 patients with falciparum malaria and 178 asymptomatic controls. A questionnaire was used to gather information on sociodemographic variables. Additionally physical examinations were carried out, stool samples were analysed for intestinal parasites and blood samples for Ig E concentrations. We found associations between infection with hookworm (OR: 4.21; 95% CI: 1.68-11.31) and Ascaris lumbricoides (OR 0.43; 95% CI: 0.18-1.04) and the occurrence of falciparum malaria. The effects of soil-transmitted helminths on the occurrence of malaria were found to be paradoxical. While hookworm is a risk factor, A. lumbricoides has a protective effect. The findings suggest that, in addition to the comorbidity, the presence of common determinants of soil-transmitted helminth infections and malaria could also exist. While the biological mechanisms involved are not clear, public health policies aimed at the control of their common social and environmental determinants are suggested.
Asunto(s)
Ascariasis/epidemiología , Helmintiasis/epidemiología , Infecciones por Uncinaria/epidemiología , Malaria Falciparum/epidemiología , Tricuriasis/epidemiología , Adolescente , Adulto , Animales , Ascariasis/microbiología , Estudios de Casos y Controles , Niño , Preescolar , Colombia/epidemiología , Comorbilidad , Heces/parasitología , Femenino , Helmintiasis/microbiología , Infecciones por Uncinaria/microbiología , Humanos , Malaria Falciparum/microbiología , Masculino , Persona de Mediana Edad , Prevalencia , Microbiología del Suelo , Encuestas y Cuestionarios , Tricuriasis/microbiologíaRESUMEN
Cecal microorganisms of mice were categorized and enumerated weekly during the developmental cycle of infection with the whipworm, Trichuris muris. The cecal bacterial population consisted of Escherichia coli, Proteus spp, Acinetobacter lwoffi (Mima polymorpha), aerobic lactobacilli, staphylococci, enterococci, and anaerobes (bacteroides, streptococci, and lactobacilli) in control and T. muris-infected mice. The aerobic lactobacilli and the anaerobes constituted the greatest number of organisms in both groups. In week three there was a decrease in the number of these organisms, and in week four fewer of these and of all other organisms in the worm-infected mice when compared to controls. The most significantly reduced bacterial counts were observed during the period of T. muris self-cure.